Ch24 Flashcards
Metals
Steel Shapes:
Metals used in structural applications (and uses)
- Steel (most common, for beams, colums, plates, studs, decking, truss joists, fasteners)
- Aluminum (small structures, portions of structures)
Steel Shapes:
Wide Flange
-Aappearance, uses, designation
- H-shaped sections used for beams and columns
- Particularly suited for columns because the width of the flange is nearly equal to the depth of the section (equal rigidity in both axes)
- Designation: W (depth) x (weight)
- Ex: W18 x 35
Steel Shapes:
American Standard I-Beam
-Appearance, uses, designation
- Relatively narrow flange width in relation to depth
- Inside faces of flanges have 1:6 slope
- Used as beams
- Designation: S (depth) x (weight)
- Ex: S12 x 35
Steel Shapes:
American Standard Channel Section
-Appearance, uses, designation
- Flange on one side of web
- Used to frame openings, to form stair stringers, other applications where flush side is needed
- Designation: C (depth)x(weight)
- Ex: C15 x 40
Steel Shapes:
Structural Tee
-Appearance, uses, designation
- Wide flange or I-Beam cut in half
- Designation: WT or ST (depth)x(weight)
- WT if cut from wide flange, ST if cut from I Beam
- Ex: WT7 x 15 or ST9 x 35
Steel Shapes:
Steel Angles
(appearance, uses, designation)
- Used as lintels, in pairs as members for steel trusses, and for miscellaneous bracing
- Equal or unequal legs
- Designation: L (length 1)x(length 2)x(thickness of legs)
- Ex: L3 x 3 x 3/8 or L3 x 4 x 1/2
Steel Shapes:
Structural Tube
(appearances, uses, designation)
- Square or rectangular tube section
- Used for light columns and as truss and space frame members
- Designation: TS (length1)x(length2)x(wall thickness)
- Ex: TS8 x 8 x 0.03750
Steel Shapes:
Structural Pipe
(appearances, uses, designation)
- Round steel pipe, available in 3 weights (standard, extra strong, double extra strong)
- Used for light columns and as truss and space frame members
- Designation: pipe (nominal diameter) (weight)
- Ex: pipe 4 std.
Steel Shapes:
Steel Bars
- Any rectangular section 6 inches or less in width with a thickness of 0.203 inches and greater
or - Sections 6 inches to 8 inches wide with a thickness of 0.230 inches and greater
Steel Shapes:
Steel Plates
- Any section over 8 inches wide with a thickness of 0.230 inches and over
or - Any section over 48 inches wide with a thickness of 0.180 inches and over
Open web steel joist:
-Appearance and Composition
- Shop-fabricated trusses with webs composed of linear members and chores of back-to-back steel angles
- Chords are typically parallel, but some have top chords that are pitched for roof drainage
Open web steel joist:
-Series (name, spans, and depths)
- K-series (standard series, 8-60 ft spans, 8-30 in depths @ 2 inch increments)
- LH-series (long span series, 25-96 ft spans, 18-48 in depth @ 4 inch increments)
- DLH-series (deep long span series, 89-144 ft spans, 52-96 in deep @ 4 inch increments)
Open web steel joist:
-Designation
- Depth, Series, Type
- Ex: 36LH13 is 36 inches deep, LH-series, Type 13
- Chord type number increases as load capacity of that depth of joist increases
Open web steel joist:
-Advantages
- Lightweight and efficient
- Quick and easy to erect
- Allows for ductwork and services to run through joists
- Can be used with variety of floor decking types
- Easily supported by steel beams, masonry, concrete, or other steel members
Open web steel joists:
-Composite wood and steel joists
- Use wood for top and bottom chords, steel for webs
- Ideal for wood-frame buildings where wood decking is used and where spans exceed limit of standard wood joists
Metal Decking
- Definition and benefits
- Steel or aluminum panels laid over steel beams or open web steel joists to serve as formwork for poured concrete slabs
- Available in variety of types, shapes, depths, and gauges to satisfy nearly any span and loading condition
- Provides structural support and raceways for power and cabling
Light gauge metal framing:
-Definition, uses, and benefits
- Steel members (10 to 25 gauge) for wall framing, joists, rafters, and similar
- Shapes more suitable for lighter loads and easier handling
- Most common for interior partitions in noncombustible buildings
- Noncombustible, easily cut and assembled, does not shrink or decay
Light gauge metal framing:
- Dimensions for interior partitions (gauges and depths)
- 20 to 25 gauge most common
- 1-5/8, 2-1/2, 3-5/8, 4, 6 inch depths most common
- Heavier gauges and depths available for higher walls, bearing walls, exterior walls
Light gauge metal framing:
- Sizes for joists and rafters (gauges, depths, spans)
- 10 to 20 gauge
- 6 to 14 inch depth
- up to 40 foot spans
Light gauge metal framing:
- Erection methods
- Screws, bolts, or welds, depending on thickness of member and its application
Metal Fabrications
- Individual building components fabricated partially or entirely of steel, aluminum, or other metals
Metal Fabrications:
Spiral Stairs
-Treads
-Exposed steel, hardwood over steel support, recessed steel pans for infill with concrete or stone, or particleboard over steel support that can be finished with carpet or resilient flooring
Metal Fabrications:
Spiral Stairs
-Standard dimensions
- Diameters: 3’-6” to 7’-0”, in 6” increments
- Tread angles: 22.5, 27, or 30 degrees (most common, has 12 treads in a full 360 spiral)
- Risers: 7-1/2” to 9-1/2”
Metal Fabrications:
-Expansion Joints
- Designed to allow for major movement (1/2” or more) between independent structural units of the building
- May allow for lateral movement only, or lateral and vertical movement
- Seismic joints also available, but require further study to determine requirements
Metal Fabrications:
-Miscellaneous
- Gratings, steel ladders, stair treads, pipe handrails and guardrails, sheet metal enclosures, prefabricated utility stairs, protective steel bollards, bumpers, corner guards
Ornamental Metals:
-Types of metals
- Stainless steel, copper alloys (bronze and brass), aluminum
- Carbon steel, copper, iron, porcelain enamel are less common
Detailing Stainless Steel:
-Joining
- Welding (smoothest, but can’t always match finish)
- Mechanical fasteners (should also be stainless steel to prevent galvanic action and rusting)
- Adhesives (used to laminate sheet stock to other materials)
Detailing with Brass and Bronze
-Extruding and Casting
- Extruding most common for door and window frames, railings, and trim
- Casting common for hardware and plumbing fixtures
Detailing with Brass and Bronze
-Shapes
- Tubing (square, rectangular, and round)
- Angles (equal or unequal legs)
- Channels (equal or unequal)
- Bars (rectangular, bar, rod)
- Special order, T-shapes, Z-shapes, and proprietary shapes also available
Detailing with Brass and Bronze
-Sheets and gauges (large sheets, lamination, brake-formed brass)
- For large expaneses of smooth, flat sheet stock, gauge must be thick enough to avoid oil canning or showing imperfections (min. 10 gauge)
- Thinner gauge possible if sheet has embossed pattern because pattern imparts stiffness to sheet
- Brass laminated to backing can be as thin as 20 gauge
- Items fabricated of brake-formeds brass are 14- or 12-gauge
Detailing with Brass and Bronze
-Joining
- Mechanical fasteners (screws, bolts, clips, rivets; usually concealed if possible)
- Adhesives (for laminating sheets or to join small pieces to other materials
- Brass can be joined by brazing, soldering, and welding (brazing most common)
Perforated Metals
- Sheet metal punched with a regular pattern of holes
square, round, or slots in a variety of patterns, sizes, and spacing
Architectural Mesh
- Specialty metal most often used for elevator cab interiors, formed by weaving thin strips of metal or heavy wire, then grinding off a portion of one face to reveal a highly textured by relatively flat surface
- Stainless steel and brass are most common
